1. Field of the Invention
The disclosure relates to a mobile communication device. More particularly, the disclosure relates to a mobile communication device capable of broadband or multiband operation.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98.
Because of the demand of increasing the capacity and speed of mobile telephone networks for mobile users, the long term evolution (LTE) system has been proposed. The LTE system could provide better mobile broadband and multimedia services than the existing GSM/UMTS mobile networks so it is expected to be very attractive for the mobile users in the near future. Besides, the LTE system could also support the existing GSM/UMTS operation; this makes ubiquitous mobile broadband coverage very promising to become a reality. For this application, a mobile communication device equipped with a compact antenna which can cover the LTE/GSM/UMTS operation has become an important research topic recently. However, it is difficult to design a single internal antenna to cover the required wide bandwidth (698˜960 MHz and 1710˜2690 MHz) of the operating bands for the LTE/GSM/UMTS operation in a mobile communication device which generally offers limited space for internal antennas. In view of the bandwidth of the operating bands of the antennas used in the current mobile communication devices, most of them could not achieve the bandwidth requirement for the LTE/GSM/UMTS operation. The multiband operation could be achieved by designing an open loop antenna integrated with an additional shorted parasitic monopole strip; however, the operating bands of the antenna cover only GSM900/GSM1800/GSM1900/UMTS systems for quad-band operation. Although adding an additional shorted parasitic monopole strip for an antenna could provide an additional resonant path for generating a new resonant mode to improve the operating bandwidth of the antenna, such a design approach would increase the required size of the antenna.